A Ring Transducer System for Medical

Waag, Robert C.; Fedewa, Russell J.

doi:10.1109/tuffc.2006.104

Cited by 48 publications

(30 citation statements)

References 34 publications

(35 reference statements)

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“…For these parameter values that were chosen to model the pulse and the focusing in the ring transducer system described in Ref. 3, the −3 dB width in elevation is 2.1 mm and remains the same as the transmit-receive angle varies, and the −3 dB focal length increases monotonically from 72.1 mm at a transmit-receive angle of 180°to 125.6 mm at a transmit-receive angle of 90°. The corresponding values for the −6 dB width in elevation and the range of the −6 dB focal length are 3.2 mm and 124.9-150.0 mm, respectively.…”

Section: Numerical Resultsmentioning

confidence: 99%

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Scattering calculation and image reconstruction using elevation-focused beams

Duncan

Astheimer

Waag

2009

The Journal of the Acoustical Society of America

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Pressure scattered by cylindrical and spherical objects with elevation-focused illumination and reception has been analytically calculated, and corresponding cross sections have been reconstructed with a two-dimensional algorithm. Elevation focusing was used to elucidate constraints on quantitative imaging of three-dimensional objects with two-dimensional algorithms. Focused illumination and reception are represented by angular spectra of plane waves that were efficiently computed using a Fourier interpolation method to maintain the same angles for all temporal frequencies. Reconstructions were formed using an eigenfunction method with multiple frequencies, phase compensation, and iteration. The results show that the scattered pressure reduces to a two-dimensional expression, and two-dimensional algorithms are applicable when the region of a three-dimensional object within an elevation-focused beam is approximately constant in elevation. The results also show that energy scattered out of the reception aperture by objects contained within the focused beam can result in the reconstructed values of attenuation slope being greater than true values at the boundary of the object. Reconstructed sound speed images, however, appear to be relatively unaffected by the loss in scattered energy. The broad conclusion that can be drawn from these results is that two-dimensional reconstructions require compensation to account for uncaptured three-dimensional scattering.

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Section: Numerical Resultsmentioning

confidence: 99%

“…3 The transducer in this system is a 150-mm diameter ring of 2048 equally spaced transducer elements each with an elevation of 25 mm. The elements are focused in elevation with an acoustic lens that creates a beam with an elevation f-number of 5.…”

Section: 2mentioning

confidence: 99%

Scattering calculation and image reconstruction using elevation-focused beams

Duncan

Astheimer

Waag

2009

The Journal of the Acoustical Society of America

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“…A toroidal array architecture can now be built owing to recent progress in solid-state electronics and array micro-machining that allows a large number of scattering experiments to be performed in a very short period of time. For instance, prototype toroidal arrays with as many as 1024 (Andre et al 1997), or more recently, 2048 (Waag & Fedewa 2006), transreceivers have been manufactured and can collect all the possible transmit-receive pairs in less than a second. Acquisition speed is crucial for clinical applications to avoid motion artefact and limit examination time.…”

Section: Synthetic Aperture Diffraction Tomographymentioning

confidence: 99%

Synthetic aperture diffraction tomography for three-dimensional imaging

Simonetti

Huang

2009

Proc. R. Soc. A.

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Tomography of complex three-dimensional objects with ultrasound or microwave has been a long-standing goal since the introduction of these technologies after World War II. While current state-of-the-art systems can provide high-resolution images of cylindrical objects characterized by a two-dimensional structure, the three-dimensional case remains an open challenge owing to current limitations of sensor technology and computer power. Here, this problem is addressed by means of a synthetic aperture technique that, while using hardware technology developed for two-dimensional problems, accounts for the complexity of three-dimensional scattering and leads to high-resolution three-dimensional reconstructions. In this paper, we present the theoretical formulation of this new approach and illustrate it by means of a numerical example.

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“…These differences in mechanical properties result in ultrasound scattering, particularly in dense breasts. With the development of new circular ultrasound arrays for clinical breast imaging, [4][5][6][7][8][9][10] heterogeneous sound-speed distributions of the breast can be reliably reconstructed using ultrasound tomography. [11][12][13][14][15][16] Ultrasound reflection images can be significantly improved by using the heterogeneous sound-speed distribution of the breast during reflectivity image reconstruction.…”

Section: Introductionmentioning

confidence: 99%

Globally optimized Fourier finite-difference method for ultrasound breast imaging

et al. 2008

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Ultrasound reflection imaging is a promising imaging modality for detecting small, early-stage breast cancers. Properly accounting for ultrasound scattering from heterogeneities within the breast is essential for high-resolution and high-quality ultrasound breast imaging. We develop a globally optimized Fourier finite-difference method for ultrasound reflectivity image reconstruction. It utilizes an optimized solution of acoustic-wave equation and a heterogeneous sound-speed distribution of the breast obtained from tomography to reconstruct ultrasound reflectivity images. The method contains a finite-difference term in addition to the split-step Fourier implementation, and minimizes ultrasound phase errors during wavefield inward continuation while maintaining the advantage of high computational efficiency. The accuracy analysis indicates that the optimized method is much more accurate than the split-step Fourier method. The computational efficiency of the optimized method is one to two orders of magnitude faster than time-reversal imaging using a finite-difference time-domain wave-equation scheme. Our new optimized method can accurately handle ultrasound scattering from breast heterogeneities during reflectivity image reconstruction. Our numerical imaging examples demonstrate that the optimized method has the potential to produce high-quality and high-resolution ultrasound reflectivity images in combination with a reliable ultrasound sound-speed tomography method.

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A Ring Transducer System for Medical

Cited by 48 publications

References 34 publications

Scattering calculation and image reconstruction using elevation-focused beams

Scattering calculation and image reconstruction using elevation-focused beams

Synthetic aperture diffraction tomography for three-dimensional imaging

Globally optimized Fourier finite-difference method for ultrasound breast imaging

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